The equation is
.
Distribute terms using distributive property:
.

(Multiply:
)
Apply addition property of equality: If a = b then a + b = b + a.
\
(Apply additive inverse property:
)
(Apply additive identity property:
)
(Add:
)
Apply division property of equality: If a = b then
.
(Divide each side by 2)
(Cancel common terms)
(Divide:
)
Check:
\To check the solution, and substitute x = 12, in
.
(Substitute
)
(Subtract :
)
(Multiply:
)
The equation is true.
The solution of
.